Wireless charging is now prevailing and it is certain that in the future, wireless charging can be done everywhere.
Wireless charging everywhere provides great convenience, but surges that occur in charging operations, both wired and wireless charging, causes accumulated damage to the rechargeable batteries and the shortening, in an progressive manner, the lifespan of the batteries. In other words, the more times charging has been done, the shorter the lifespan of the battery will be and the poorer the charging/discharging efficiency of the battery will be.
In a wireless charging everywhere environment, the sphere of activity of human beings must be provided with a variety of charging sites, or people may frequently pass through the charging site. Under this condition, the portable electronic device carried by their owners will be definitely subjected to charging several times in a single day and this surely shortens the lifespan of the batteries contained in the portable electronic devices.
Further, since wireless power transmission is still of low efficiency today, meaning the amount of discharged electricity is greater than the amount of charged electricity. In addition, the step-up/step-down conversion is also of low efficiency heretofore. All these make wireless power transmission impractical and this has been concerned by general consumers for quite a long time.
Thus, the present invention aims to provide a wireless charging device that protects a rechargeable battery from accumulated damage caused by frequent charging and even improves the efficiency of wireless power transmission and efficiency of step-up and step-down conversions.